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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License version 2.
*/
#include "lock_dlm.h"
/* A lock placed on this queue is re-submitted to DLM as soon as the lock_dlm
thread gets to it. */
static void queue_submit(struct gdlm_lock *lp)
{
struct gdlm_ls *ls = lp->ls;
spin_lock(&ls->async_lock);
list_add_tail(&lp->delay_list, &ls->submit);
spin_unlock(&ls->async_lock);
wake_up(&ls->thread_wait);
}
static void process_blocking(struct gdlm_lock *lp, int bast_mode)
{
struct gdlm_ls *ls = lp->ls;
unsigned int cb = 0;
switch (gdlm_make_lmstate(bast_mode)) {
case LM_ST_EXCLUSIVE:
cb = LM_CB_NEED_E;
break;
case LM_ST_DEFERRED:
cb = LM_CB_NEED_D;
break;
case LM_ST_SHARED:
cb = LM_CB_NEED_S;
break;
default:
gdlm_assert(0, "unknown bast mode %u", lp->bast_mode);
}
ls->fscb(ls->sdp, cb, &lp->lockname);
}
static void wake_up_ast(struct gdlm_lock *lp)
{
clear_bit(LFL_AST_WAIT, &lp->flags);
smp_mb__after_clear_bit();
wake_up_bit(&lp->flags, LFL_AST_WAIT);
}
static void process_complete(struct gdlm_lock *lp)
{
struct gdlm_ls *ls = lp->ls;
struct lm_async_cb acb;
s16 prev_mode = lp->cur;
memset(&acb, 0, sizeof(acb));
if (lp->lksb.sb_status == -DLM_ECANCEL) {
log_info("complete dlm cancel %x,%llx flags %lx",
lp->lockname.ln_type,
(unsigned long long)lp->lockname.ln_number,
lp->flags);
lp->req = lp->cur;
acb.lc_ret |= LM_OUT_CANCELED;
if (lp->cur == DLM_LOCK_IV)
lp->lksb.sb_lkid = 0;
goto out;
}
if (test_and_clear_bit(LFL_DLM_UNLOCK, &lp->flags)) {
if (lp->lksb.sb_status != -DLM_EUNLOCK) {
log_info("unlock sb_status %d %x,%llx flags %lx",
lp->lksb.sb_status, lp->lockname.ln_type,
(unsigned long long)lp->lockname.ln_number,
lp->flags);
return;
}
lp->cur = DLM_LOCK_IV;
lp->req = DLM_LOCK_IV;
lp->lksb.sb_lkid = 0;
if (test_and_clear_bit(LFL_UNLOCK_DELETE, &lp->flags)) {
gdlm_delete_lp(lp);
return;
}
goto out;
}
if (lp->lksb.sb_flags & DLM_SBF_VALNOTVALID)
memset(lp->lksb.sb_lvbptr, 0, GDLM_LVB_SIZE);
if (lp->lksb.sb_flags & DLM_SBF_ALTMODE) {
if (lp->req == DLM_LOCK_PR)
lp->req = DLM_LOCK_CW;
else if (lp->req == DLM_LOCK_CW)
lp->req = DLM_LOCK_PR;
}
/*
* A canceled lock request. The lock was just taken off the delayed
* list and was never even submitted to dlm.
*/
if (test_and_clear_bit(LFL_CANCEL, &lp->flags)) {
log_info("complete internal cancel %x,%llx",
lp->lockname.ln_type,
(unsigned long long)lp->lockname.ln_number);
lp->req = lp->cur;
acb.lc_ret |= LM_OUT_CANCELED;
goto out;
}
/*
* An error occured.
*/
if (lp->lksb.sb_status) {
/* a "normal" error */
if ((lp->lksb.sb_status == -EAGAIN) &&
(lp->lkf & DLM_LKF_NOQUEUE)) {
lp->req = lp->cur;
if (lp->cur == DLM_LOCK_IV)
lp->lksb.sb_lkid = 0;
goto out;
}
/* this could only happen with cancels I think */
log_info("ast sb_status %d %x,%llx flags %lx",
lp->lksb.sb_status, lp->lockname.ln_type,
(unsigned long long)lp->lockname.ln_number,
lp->flags);
return;
}
/*
* This is an AST for an EX->EX conversion for sync_lvb from GFS.
*/
if (test_and_clear_bit(LFL_SYNC_LVB, &lp->flags)) {
wake_up_ast(lp);
return;
}
/*
* A lock has been demoted to NL because it initially completed during
* BLOCK_LOCKS. Now it must be requested in the originally requested
* mode.
*/
if (test_and_clear_bit(LFL_REREQUEST, &lp->flags)) {
gdlm_assert(lp->req == DLM_LOCK_NL, "%x,%llx",
lp->lockname.ln_type,
(unsigned long long)lp->lockname.ln_number);
gdlm_assert(lp->prev_req > DLM_LOCK_NL, "%x,%llx",
lp->lockname.ln_type,
(unsigned long long)lp->lockname.ln_number);
lp->cur = DLM_LOCK_NL;
lp->req = lp->prev_req;
lp->prev_req = DLM_LOCK_IV;
lp->lkf &= ~DLM_LKF_CONVDEADLK;
set_bit(LFL_NOCACHE, &lp->flags);
if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
!test_bit(LFL_NOBLOCK, &lp->flags))
gdlm_queue_delayed(lp);
else
queue_submit(lp);
return;
}
/*
* A request is granted during dlm recovery. It may be granted
* because the locks of a failed node were cleared. In that case,
* there may be inconsistent data beneath this lock and we must wait
* for recovery to complete to use it. When gfs recovery is done this
* granted lock will be converted to NL and then reacquired in this
* granted state.
*/
if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
!test_bit(LFL_NOBLOCK, &lp->flags) &&
lp->req != DLM_LOCK_NL) {
lp->cur = lp->req;
lp->prev_req = lp->req;
lp->req = DLM_LOCK_NL;
lp->lkf |= DLM_LKF_CONVERT;
lp->lkf &= ~DLM_LKF_CONVDEADLK;
log_debug("rereq %x,%llx id %x %d,%d",
lp->lockname.ln_type,
(unsigned long long)lp->lockname.ln_number,
lp->lksb.sb_lkid, lp->cur, lp->req);
set_bit(LFL_REREQUEST, &lp->flags);
queue_submit(lp);
return;
}
/*
* DLM demoted the lock to NL before it was granted so GFS must be
* told it cannot cache data for this lock.
*/
if (lp->lksb.sb_flags & DLM_SBF_DEMOTED)
set_bit(LFL_NOCACHE, &lp->flags);
out:
/*
* This is an internal lock_dlm lock
*/
if (test_bit(LFL_INLOCK, &lp->flags)) {
clear_bit(LFL_NOBLOCK, &lp->flags);
lp->cur = lp->req;
wake_up_ast(lp);
return;
}
/*
* Normal completion of a lock request. Tell GFS it now has the lock.
*/
clear_bit(LFL_NOBLOCK, &lp->flags);
lp->cur = lp->req;
acb.lc_name = lp->lockname;
acb.lc_ret |= gdlm_make_lmstate(lp->cur);
if (!test_and_clear_bit(LFL_NOCACHE, &lp->flags) &&
(lp->cur > DLM_LOCK_NL) && (prev_mode > DLM_LOCK_NL))
acb.lc_ret |= LM_OUT_CACHEABLE;
ls->fscb(ls->sdp, LM_CB_ASYNC, &acb);
}
static inline int no_work(struct gdlm_ls *ls, int blocking)
{
int ret;
spin_lock(&ls->async_lock);
ret = list_empty(&ls->complete) && list_empty(&ls->submit);
if (ret && blocking)
ret = list_empty(&ls->blocking);
spin_unlock(&ls->async_lock);
return ret;
}
static inline int check_drop(struct gdlm_ls *ls)
{
if (!ls->drop_locks_count)
return 0;
if (time_after(jiffies, ls->drop_time + ls->drop_locks_period * HZ)) {
ls->drop_time = jiffies;
if (ls->all_locks_count >= ls->drop_locks_count)
return 1;
}
return 0;
}
static int gdlm_thread(void *data)
{
struct gdlm_ls *ls = (struct gdlm_ls *) data;
struct gdlm_lock *lp = NULL;
int blist = 0;
uint8_t complete, blocking, submit, drop;
DECLARE_WAITQUEUE(wait, current);
/* Only thread1 is allowed to do blocking callbacks since gfs
may wait for a completion callback within a blocking cb. */
if (current == ls->thread1)
blist = 1;
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&ls->thread_wait, &wait);
if (no_work(ls, blist))
schedule();
remove_wait_queue(&ls->thread_wait, &wait);
set_current_state(TASK_RUNNING);
complete = blocking = submit = drop = 0;
spin_lock(&ls->async_lock);
if (blist && !list_empty(&ls->blocking)) {
lp = list_entry(ls->blocking.next, struct gdlm_lock,
blist);
list_del_init(&lp->blist);
blocking = lp->bast_mode;
lp->bast_mode = 0;
} else if (!list_empty(&ls->complete)) {
lp = list_entry(ls->complete.next, struct gdlm_lock,
clist);
list_del_init(&lp->clist);
complete = 1;
} else if (!list_empty(&ls->submit)) {
lp = list_entry(ls->submit.next, struct gdlm_lock,
delay_list);
list_del_init(&lp->delay_list);
submit = 1;
}
drop = check_drop(ls);
spin_unlock(&ls->async_lock);
if (complete)
process_complete(lp);
else if (blocking)
process_blocking(lp, blocking);
else if (submit)
gdlm_do_lock(lp);
if (drop)
ls->fscb(ls->sdp, LM_CB_DROPLOCKS, NULL);
schedule();
}
return 0;
}
int gdlm_init_threads(struct gdlm_ls *ls)
{
struct task_struct *p;
int error;
p = kthread_run(gdlm_thread, ls, "lock_dlm1");
error = IS_ERR(p);
if (error) {
log_error("can't start lock_dlm1 thread %d", error);
return error;
}
ls->thread1 = p;
p = kthread_run(gdlm_thread, ls, "lock_dlm2");
error = IS_ERR(p);
if (error) {
log_error("can't start lock_dlm2 thread %d", error);
kthread_stop(ls->thread1);
return error;
}
ls->thread2 = p;
return 0;
}
void gdlm_release_threads(struct gdlm_ls *ls)
{
kthread_stop(ls->thread1);
kthread_stop(ls->thread2);
}
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